In recent years, dendrites that grow in a lithium battery have been considered problematic because they may cause a short circuit within the battery, explosion of the battery, or the like. Therefore, effective inspection methods for preventing such a short circuit or the like have been researched and developed. In this regard, Patent Literature (PTL) 1 discloses a method for examining the condition of a battery by using high-brightness X-ray, visible light, or ultrasound waves.